rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3479/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=11441, q=5 ncpus=2)
task:kworker/u4:12 state:R running task stack:22936 pid:3479 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:raw_atomic_fetch_add_unless include/linux/atomic/atomic-arch-fallback.h:2407 [inline]
RIP: 0010:raw_atomic_add_unless include/linux/atomic/atomic-arch-fallback.h:2433 [inline]
RIP: 0010:atomic_add_unless include/linux/atomic/atomic-instrumented.h:1508 [inline]
RIP: 0010:page_ref_add_unless include/linux/page_ref.h:238 [inline]
RIP: 0010:folio_ref_add_unless include/linux/page_ref.h:247 [inline]
RIP: 0010:folio_try_get include/linux/page_ref.h:263 [inline]
RIP: 0010:find_get_entry mm/filemap.c:2027 [inline]
RIP: 0010:filemap_get_folios+0x22f/0x7b0 mm/filemap.c:2179
Code: 89 fb 4d 8d 7c 24 34 4c 89 ff be 04 00 00 00 e8 f7 0b 29 00 4c 89 f8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 b1 00 00 00 41 8b 1f <31> ff 89 de e8 c8 5e d0 ff 85 db 0f 84 80 00 00 00 8d 4b 01 31 f6
RSP: 0018:ffffc9000c3c6d20 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff81b53b29
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffea0002e3f434
RBP: ffffc9000c3c6e30 R08: ffffea0002e3f437 R09: 1ffffd40005c7e86
R10: dffffc0000000000 R11: fffff940005c7e87 R12: ffffea0002e3f400
R13: 00000000000007ff R14: ffffc9000c3c6d80 R15: ffffea0002e3f434
mpage_map_and_submit_buffers fs/ext4/inode.c:2138 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2293 [inline]
ext4_do_writepages+0x185a/0x38d0 fs/ext4/inode.c:2718
ext4_writepages+0x1a8/0x2f0 fs/ext4/inode.c:2807
do_writepages+0x3a2/0x600 mm/page-writeback.c:2575
__writeback_single_inode+0x153/0xee0 fs/fs-writeback.c:1625
writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1916
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1987
wb_writeback+0x464/0xba0 fs/fs-writeback.c:2097
wb_check_old_data_flush fs/fs-writeback.c:2201 [inline]
wb_do_writeback fs/fs-writeback.c:2254 [inline]
wb_workfn+0xabc/0xe20 fs/fs-writeback.c:2282
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: rcu_preempt kthread starved for 10543 jiffies! g11441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27496 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 5799 Comm: syz-executor180 Not tainted 6.6.95-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 fa 76 f7 f6 48 89 df e8 12 49 f8 f6 e8 ed f5 1b f7 fb bf 01 00 00 00 52 60 eb f6 65 8b 05 63 b6 93 75 85 c0 74 02 5b c3 e8 40 98 90
RSP: 0018:ffffc9000475fc98 EFLAGS: 00000282
RAX: 9bee2df653981100 RBX: ffff88802c500000 RCX: 9bee2df653981100
RDX: dffffc0000000000 RSI: ffffffff8aaab2c0 RDI: 0000000000000001
RBP: ffff88802c500498 R08: ffffffff8e49ac2f R09: 1ffffffff1c93585
R10: dffffc0000000000 R11: fffffbfff1c93586 R12: 1ffff110058a0093
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
FS: 000055556ebb23c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f34fe322488 CR3: 000000007af87000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x11f5/0x1400 kernel/signal.c:2905
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f34fe322488
Code: e8 3d d9 f8 ff 48 85 db 75 f0 48 8b 3d 69 9f 03 00 48 83 c5 08 48 81 fd f8 07 00 00 75 cc 48 83 c4 08 5b 5d e9 19 d9 f8 ff c3 <48> 83 ec 08 48 83 c4 08 c3 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 002b:00007fff8d78d698 EFLAGS: 00010206
RAX: 00007f34fe355ad8 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 00007f34fe356de0 RSI: 0000000000000000 RDI: 00007f34fe355ad8
RBP: 00007f34fe354130 R08: 00007f34fe28b990 R09: 00007f34fe28b990
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f34fe356dc8
R13: 0000000000000000 R14: 00007f34fe356de0 R15: 00007f34fe296f90